气相沉积聚合法制备聚酰亚胺绝缘薄膜及其性能研究

以联苯四酸二酐和4,4’-二氨基二苯醚为单体原料使用气相沉积聚合(VDP)法制备了聚酰亚胺(PI)绝缘膜,分析不同热亚胺化处理温度对PI薄膜绝缘性能的影响。分别使用红外光谱、俄歇能谱、扫描电镜、原子力显微镜对薄膜成分以及薄膜表面形貌进行了表征;利用超高阻微电流测试仪测试了PI复合绝缘膜漏电流和电压击穿特性。结果表明:热亚胺化300℃/1 h真空(1.0×10-2Pa)处理后的PI绝缘膜内部结构致密,当场强为8.0MV/cm时漏电流密仅为8.2×10-5A/cm2;薄膜击穿场强达到8.42MV/cm,表明PI薄膜具有良好的电学性能以及热稳定性。     

热和化学亚胺化对ODPA/ODA聚酰亚胺薄膜性能的影响

以4,4'-二胺基二苯醚(ODA)和3,3',4,4'-二苯醚四酸二酐(ODPA)为单体,采用两步法,分别经热亚胺化和化学亚胺化过程制备了两种聚酰亚胺(PI)薄膜,并对两种薄膜的性能进行了表征.傅立叶红外光谱(FT-IR)表明两种薄膜均已完全亚胺化.化学亚胺化的PI薄膜的玻璃化温度、热稳定性均高于热亚胺化的薄膜.拉伸性能测试表明热亚胺化的薄膜具有较高的断裂伸长率,而化学亚胺化的薄膜的拉伸强度、弹性模量较大.     

聚酰亚胺薄膜老化过程中的结构与性能演变机理研究

制备了BPDA/ODA、BP DA/PDA和PMDA/ODA体系的聚酰亚胺(PI)薄膜，探究不同化学结构的PI薄膜在热氧和紫外辐照等外界环境条件下的结构与性能演变。力学性能测试表明，热氧和紫外辐照会导致PI薄膜力学性能下降，但不同化学结构的PI薄膜下降趋势不同，其中PMDA/ODA下降最快，BPDA/PDA下降最慢。红外测试结果表明，热氧和紫外辐照老化过程中酰亚胺环中的C—N键最先发生断裂，导致PI薄膜亚胺化程度降低，力学性能下降。此外，电子自旋共振光谱仪相对其他表征方法在PI薄膜老化初期可以较为直观地检测到自由基浓度随老化时间的变化，可作为PI材料早期老化诊断的手段。     

热塑性共聚聚酰亚胺薄膜的合成及性能研究

以2,2′-二甲基-4,4′-二氨基联苯(m-TB)为二胺单体,均苯四甲酸二酐(PMDA)和3,3′,4,4′-联苯四甲酸二酐(BPDA)为二酐单体,N,N′-二甲基乙酰胺(DMAc)为溶剂,采用常规的两步法制备了一系列不同二酐比例的热塑性聚酰亚胺,并通过红外光谱仪、X-射线衍射仪、热重分析仪、紫外光谱仪、动态热分析仪、溶解性测试等对共聚聚酰亚胺的结构和性能进行表征.结果表明:在1 780、1 720、1 500、1 380、1 050和725 cm~(-1)处出现明显的吸收峰,说明成功制备了聚酰亚胺材料;共聚聚酰亚胺只在PMDA与BPDA物质的量比为0.2∶0.8时存在结晶峰,其他比例时均为非晶聚合物;亚胺化后的共聚聚酰亚胺在DMSO、DMAc、DMF、NMP和m-cresol中有溶解性,证明成功制备出热塑性聚酰亚胺薄膜;热塑性共聚PI起始分解温度大于500℃,800℃时的质量保持率在50%以上,具有良好的热稳定性;随着聚合物中BPDA含量的提高,热塑性聚酰亚胺薄膜的玻璃化转变温度呈现下降的趋势.当紫外光波长达到400 nm时,薄膜的透光率高达57.6%,当波长为760 nm时,薄膜透光率均达到100%,成功制备了透光率较高的聚酰亚胺薄膜.     

共缩聚型聚酰亚胺薄膜的制备及其性能的研究

采用不同摩尔比的均苯四甲酸二酐(PMDA)、2,2′,3,3′-联苯四甲酸二酐(i-BPDA)的混合二酐与二氨基二苯醚(ODA)进行共聚反应,得到聚酰胺酸,经过程序控制热亚胺化制备聚酰亚胺薄膜。通过对力学性能、热学性能和电性能进行测试,结果表明随着i-BPDA比例的增加扯断伸长率显著增加,当PMDA与i-BPDA的摩尔比为90∶10时,PI膜的综合性能优异。     

笼型聚倍半硅氧烷增韧3层聚酰亚胺薄膜的制备与性能

以3,3′,4,4′-联苯四酸二酐(BPDA)-对苯二胺(PDA)/4,4′-二苯醚二胺(ODA)型聚酰亚胺为芯层,将2,2′-双(4-(4-氨基苯氧基)苯基)丙烷(BAPP)-BPDA型聚酰胺酸涂覆于芯层的上、下表面并热亚胺化得到3层聚酰亚胺薄膜。为提高3层聚酰亚胺薄膜的韧性,将降冰片烯二酸酐-马来酰亚胺基七异丁基聚倍半硅氧烷交替共聚物(poly(MIPOSS-alt-NA))作为BPDA的共单体引入到上、下表层的热塑性聚酰亚胺中。结果表明,当poly(MIPOSS-alt-NA)的质量分数为6.0%时,3层聚酰亚胺薄膜的断裂伸长率从7.2%提高到14.5%,热膨胀系数则从27.0×10-6 K-1降低至23.6×10-6 K-1,与铜箔制备的柔性覆铜板剥离强度达到12.0 N/cm,针对拉伸断面电镜照片的变化对增韧机理进行了分析。     

含有氢键的聚酰亚胺薄膜的制备和性能表征

以对硝基苯甲酸为原料,通过酰氯化、酰化、还原反应成功合成了4,4’-二氨基苯酰替苯胺(DBN),DBN分别和3,3’,4,4’-联苯四酸二酐(BPDA)、均苯四甲酸二酐(PMDA)通过两步法缩聚制备出聚酰亚胺薄膜,用红外(FT-IR),差示扫描量热仪(DSC)和热重分析(TGA),拉伸测试表征其结构和性能,结果表明,成功合成了含有酰胺键的聚酰亚胺薄膜,并且酰胺键的N-H分别和酰亚胺环中的C-N和C=O形成了氢键。将其与4,4’-二氨基二苯醚(ODA)聚酰亚胺薄膜相比,对应二酐(BPDA和PMDA)分别和DBN制备的聚酰亚胺薄膜表现出了优异的热性能和耐溶剂性,尤其是拉伸强度有了显著的提高。     

离子液体改性聚酰亚胺石墨膜的制备与性能研究

为确保电子设备的正常运行和安全工作，围绕电子元器件热管理的研究近年来热度持续升高，聚酰亚胺(PI)作为基材生产的石墨膜是一种重要的导热材料，且能通过掺杂改性提高石墨膜的导热性能。而相较于固体导热填料，离子液体与聚酰亚胺基体的相容性更好，已常见于气体分离膜、无色聚酰亚胺(CPI)等应用。以4,4′-二氨基苯酰替苯胺(DABA)与3,3′,4,4′-联苯四甲酸二酐(BPDA)作为单体，利用1-乙基-3-甲基咪唑双三氟甲磺酰亚胺盐(IL)这一具有多个氢键位点的IL对PI薄膜进行改性，而后通过石墨化制备得高导热石墨膜。研究结果表明，IL含量为5.0%(质量分数)时，石墨膜晶粒尺寸为78.417 nm,石墨化程度达88%,导热系数达770 W/m·K,为纯PI基石墨膜的1.53倍。     

静电纺丝技术制备耐高温聚酰亚胺无纺布膜及其性能表征

利用3,3′,4,4′-二苯甲酮四羧酸二酐(BTDA)和4,4′-二氨基二苯醚(ODA)合成得到聚酰胺酸(PAA)纺丝液,采用静电纺丝技术制备得到PAA无纺布膜,通过热亚胺化法获得聚酰亚胺(PI)无纺布膜。用扫描电子显微镜(SEM)考察了溶液浓度、纺丝距离、纺丝电压和针头大小对PAA无纺布膜形貌的影响。同时比较了热亚胺化前后PAA和PI无纺布膜的形貌变化。分别采用傅里叶变换红外光谱(FT-IR)、热重分析(TGA)和X射线衍射(XRD)表征了它们的化学结构、热稳定性和结晶性。结果表明,制备得到的PI无纺布膜具有优良的耐热性能和微孔结构,使其在耐热分离技术领域有极大的应用价值。     

亚胺化温度对聚酰亚胺纳米纤维结构和性能的影响

利用3,3′,4,4′-二苯甲酮四羧酸二酐(BTDA)和4,4′-二氨基二苯醚(ODA)合成得到聚酰胺酸(PAA)纺丝液,采用静电纺丝技术制备得到PAA纳米纤维,通过热亚胺化法获得BTDA-ODA型聚酰亚胺(PI)纳米纤维。用扫描电子显微镜(SEM)表征了热亚胺化前后纳米纤维的形貌特征,利用傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)和热重分析(TGA)表征了不同亚胺化温度对PI纳米纤维的化学结构、结晶性能和热稳定性的影响。结果表明,当亚胺化热处理温度较低时,PAA纳米纤维的亚胺化程度较差。当亚胺化温度达到300℃时,PAA纳米纤维的亚胺化程度基本完全。随着亚胺化温度的升高,纳米纤维的结晶度逐渐增强,热稳定性也逐渐升高。     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to     

Win-Win Cooperation

正The Chinese Premier Li Keqiang's recent trip to the UK has reinforced the China-UK comprehensive strategic partnership;just as the British Prime Minister David Cameron put it,"the relationship is gaining in strength,depth and understanding"after a bucket of business deals being inked worth more than 30 billion US dollars.From the first agreement signing in 2004 to the new agreement of mutual standards recognition and adoption in     

Systematic Approach for Emerging Industry

正A national directory of standards complexes for strategic emerging sectors was recently developed and released jointly by 12governmental departments,namely,SAC,NDRC,MOST,MIIT,MEP,MOA,AQSIQ,State Forest Administration,State Administration of Science and Technology for National Defense,State Oceanic Administration and National Railway Administration.     

Strictest Pollutants Emission Standards

正Four new national standards on air pollutant emission control offi cially issued by the Ministry of Environment Protection(MEP)together with AQSIQ and SAC has been brought into force from July 1,2014.The Emission standard for air pollutants of coal-burning,oil-burning and gasfi red boilers,which is the strictest emission standard historically,will tackle the stubborn pollution problem of boilers and waste incineration in most of China’s regions.     

Instructions to Authors

New Carbon Materials is a bimonthly journal published with the permission of the Ministry of Science and Technology and of the State News and Publication Agency.The journal is sponsored by the Institute of Coal Chemistry,Chinese Academy of Sciences,and is published by Science Press.Aims and Scope     

Progress on Standards Copyright Protection

正Recently,National Copyright Administration of China(NCAC)has rewarded 215 organizations and 179 individuals for their outstanding efforts on investigating standards copyright infringement and piracy in 2013.Hua Jianhua,the Deputy-Director of National Standards Copyright Protection Workgroup Office won a third prize of the national individual award.In 2012,SAC set up the national standards copyright protection working group,and developed policies to crack down standards infringement and piracy behaviors and to strengthen standards copyright protection.